My first home office storage was a plastic file crate from a drugstore, the kind with a lid that never quite sat flat, and it taught me that cheap plastic doesn't hold paper so much as trap it, everything inside went soft and curled within a year from the damp in my old apartment. I use it for holiday decorations now, which tells you everything about where it belongs.
If you've got nothing right now and you're starting from zero, I'd get one solid box or file holder before anything decorative, something with a lid that actually closes and corners that don't flex when you pick it up full. That's the whole job in the beginning, one container that keeps paper flat and dry while you figure out what you actually need to store. Where it goes matters more than people admit. A stack of open bins under a desk looks fine for about two weeks and then becomes a pile of cables and old mail that nobody wants to deal with, so if you're short on space, go vertical instead, a narrow unit with a few drawers against a wall does more than three bins ever will, and it won't fight with a small room the way floor clutter does. Open baskets are lovely for blankets and toys but they're the wrong call for anything with paper in it, dust gets in, cats get in, and important things end up creased at the bottom under a phone charger nobody remembers plugging in. The difference between a storage piece that lasts and one that lets you down shows up fast once you're actually using it. Pick it up empty and it should have some weight to it, a hollow, light box usually means thin material that'll bow under a stack of folders within months. Drawers should slide without you having to lift the front end, and they should close with a soft, solid sound, not a rattle. Check the joints on anything wood or wood look, a well made drawer box has corners that are glued or jointed, not just stapled through the side, and a good finish feels smooth and sealed, not rough or tacky under your thumb. Lids and doors should sit flush when closed, if there's a gap you can see light through, that's where dust and damp get in over time. Fabric covered bins should feel tightly woven, not stretchy, because stretchy fabric sags within a year and never looks right again no matter how you fold things inside.
Before you buy anything, measure the exact spot you're putting it in and the height of your desk too, because storage that's an inch too tall under a desk is storage you'll be shoving around with your foot forever.